Qt5.4 beta. Cannot change Camera.viewfinder's params

I compile Qt5.4 for embedded platform I.MX6Q and try use QML Camera. I cannot change values of viewfinder property of Camera - minimumFrameRate, maximumFrameRate and resolution. Changing the settings does not change the actual settings of the camera and the picture on the preview is the same.
Also, the property of Camera viewfinder have wavy underlining in QtCreator editor .
If I query the values of these parameters I got 0, 0 and QSize(-1, -1).